[解決済み】CSS "margin: 0 auto" が中央揃えにならない。

.container {
  margin: 0 auto;
}

[class*='col-'] {
  float: left;
}

.col-2-3 {
  width: 66.66%;
}

.col-1-3 {
  width: 33.33%;
}

.grid:after {
  content: "";
  display: table;
  clear: both;
}

.col-word {
  width: auto;
  height: auto;
  padding: 25px;
  border: 5px #000 solid;
  border-left: 0px;
  border-right: 0px;
  background-color: #A7F4F6;
  font-size: xx-large;
  text-align: center;
}

<div class='container'>
  <div class="grid">
    <div class='grid'>
      <div class="col-1-3">
        <p class='col-word'>T</p>
        <p class='col-word'>V</p>
      </div>
    </div>

    <div class='grid'>
      <div class='col-1-3'>
        <div class='letter'>W</div>
      </div>
      <div class='col-1-3'>
        <div class='letter'>P</div>
      </div>
      <div class='col-1-3'>
        <div class='letter'>V</div>
      </div>
    </div>
  </div>
</div>